<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title></title>
    <style media="screen">
    .box {
      width:200px; height:200px; background:#CCC; margin:100px auto 0;
      transition: 1s all ease;
      transform:perspective(10000px) rotateY(0);
    }
    .box:active {transform:perspective(10000px) rotateY(60deg);}
    </style>
  </head>
  <body>
    <div class="box">aaa</div>
  </body>
</html>
